Infections due to methicillin-resistant Staphylococcus aureus (MRSA) have increased markedly over the past 20 years and are associated with significant excess morbidity, mortality, and cost. Person to person spread plays a central role in the emergence of MRSA in healthcare settings. As such, hospitalized patients colonized or infected with MRSA are typically placed on contact precautions to help prevent spread of MRSA. Historically, the primary way in which a hospitalized patient was identified as being MRSA colonized was via cultures obtained for clinical indications. More recently, active surveillance strategies (i.e., swabbing the nares in asymptomatic patients) have been proposed to identify a larger proportion of patients colonized with MRSA. However, the comparative effectiveness and cost effectiveness of different MRSA screening strategies are poorly defined. Moreover, no rigorous data exist in the long term care setting. In 2009, the national Veterans Health Administration (VHA) system instituted a uniform active surveillance initiative in which all patients admitted to long term care centers (LTCCs) are screened for MRSA. As a comprehensive screening approach with standardized methods implemented across multiple LTCCs, this initiative provides a unique, real world, opportunity to assess the comparative effectiveness and cost effectiveness of different MRSA screening strategies specifically in the long-term care setting The specific aims will assess the comparative effectiveness and cost effectiveness of two MRSA screening strategies in the LTCC setting (i.e., clinical culture screening and active surveillance screening) in LTCCs. The active surveillance screening strategy involves swabbing the nares in asymptomatic patients, as opposed to a clinical culture screening strategy, whereby cultures are obtained only for clinical indications. Aim 1: To assess the comparative effectiveness of the two strategies in preventing MRSA acquisition Aim 2: To assess the comparative effectiveness of the two strategies in preventing MRSA infection Aim 3: To assess the cost effectiveness of the two strategies in preventing MRSA infection The primary hypothesis for Aims 1 and 2 is that active surveillance screening will be associated with significant decreases in MRSA acquisition and infection. The primary hypothesis for Aim 3 is that the active surveillance screening strategy will be cost-effective. The clinical and public health significance of the proposed project is great in that the approach identified as most favorable will then be advocated more broadly to effectively curb MRSA transmission in the long-term care population. Elucidating the individual and institution level variables which affect the impact of these screening strategies will be critical in informing future MRSA screening interventions. Determination of the comparative effectiveness and cost effectiveness of an active screening strategy for MRSA is vital to support real-world adoption decisions.